Polar materials, with intrinsic polarization effects, present significant potential for photo(electro)catalysis. However, the available natural polar materials in this field are quite scarce, due to ...the requisite structural non‐centrosymmetry. Defect engineering emerges as a promising avenue for tuning material symmetry, yet achieving the transition from centrosymmetric to non‐centrosymmetric structures and optimizing associated polarization effects remains challenging. This study demonstrates symmetry breaking in centrosymmetric 3R‐delafossite AgFeO2 through ordered oxygen defects introduction, yielding substantial macroscopic polarization. The transition is achieved via annealing post‐treatment of co‐precipitation‐hydrothermal AgFeO2 samples, with precision in oxygen defects control by tailoring annealing conditions. Experimental characterizations reveal ordered interstitial oxygen and disordered oxygen vacancies. Density functional theory calculations indicate a higher propensity for the formation of disordered oxygen vacancies compared to ordered ones, while ordered interstitial oxygen is more easily formed than its disordered counterpart. Resultant macroscopic polarization enhances photoelectrochemical performance, with photocurrent density increasing from 0.79 to 2.95 µA cm−2. Coupling macroscopic and spin polarization via external electric and magnetic fields further enhances photocurrent density (≈18.44 µA cm−2). These findings provide reference cases and strategies for applying polarization effects in photo(electro)catalytic technology.
Oxygen defect engineering is employed to break symmetry and induce macroscopic polarization in AgFeO2 photocathodes, significantly boosting PEC performance. Ordered interstitial oxygen incorporation results in a substantial photocurrent density enhancement, and the application of external electric and magnetic fields further amplifies this effect, demonstrating a synergistic strategy and multi‐physics field coupling for further improving solar‐to‐hydrogen conversion efficiency.
•The dynamic recrystallization behavior of a typical nickel-based superalloy is investigated.•The segmented models are proposed to describe the kinetics of DRX for the studied superalloy.•The ...dynamically recrystallized grain size can be well characterized by a function of Z parameter.
The dynamic recrystallization (DRX) behavior of a typical nickel-based superalloy is investigated by the hot compression tests. Based on the conventional DRX kinetics model, the volume fractions of DRX are firstly estimated. Results show that there is an obvious deviation between the experimental and predicted volume fractions of DRX when the forming temperature is below 980°C, which is induced by the slow dynamic recrystallization rate under low forming temperatures. Therefore, the segmented models are proposed to describe the kinetics of DRX for the studied superalloy. Comparisons between the experimental and predicted results indicate that the proposed segmented models can give an accurate and precise estimation of the volume fractions of DRX for the studied superalloy. In addition, the optical observation of the deformed microstructure confirms that the dynamically recrystallized grain size can be well characterized by a power function of Zener–Hollumon parameter.
Clinopodium chinense (Benth.) O. Ktze is a traditional Chinese herbal medicine, which comprises the plant's total flavonoids. TFCC plays an important role in the treatment of cardiovascular disease.
...The aim of the study was to study the protective effects and possible mechanism of TFCC against isoproterenol (ISO)-mediated myocardial injury in vivo and anoxia/reoxygenation (A/R)-induced H9c2 cell injury in vitro.
Male Sprague–Dawley (SD) rats were intragastrically pretreated with TFCC for 15 days. After 2 h of TFCC administration on days 14 and 15, a myocardial injury model was established with intragastric administration of 120 mg/kg of ISO daily for 2 days. The experiment was stopped 12 h after the last administration of the drugs. ECG recordings were taken after the treatment. Serum samples were assayed to determine the serum cardiac enzymes (e.g., creatine kinase, aspartate aminotransferase, and lactate dehydrogenase). The left ventricle was excised for histopathological examination, and myocardial homogenates were prepared to detection catalase, glutathione peroxidase, and superoxide dismutase. Reactive oxygen species (ROS), heme oxygenase-1(HO-1),and peroxidase were detected by the corresponding ELISA kits. H9c2 cells were pretreated with different concentrations of TFCC for 12 h before A/R exposure. Afterward, cell viability, LDH release, hoechst 33,342, and peromide iodine (PI) double staining, JC-1 staining, and ROS examination were determined. Western blot analyses of B-cell lymphoma-2, Bcl-2associated X protein, cleaved cysteinylaspartate specific protease-3 and-9, nuclear factor 2(Nrf2), HO-1 and serine/threonine protein kinase (AKT), and P-AKT were conducted.
The pretreatment of TFCC (10, 20, and 40 mg/kg) daily for 15 days prevented ISO-induced myocardial damage, including the decrease in serum cardiac enzymes and cardiomyocyte apoptotic index and improvement in the heart rate and vacuolation. TFCC also improved the free radical scavenging and antioxidant potential, thereby suggesting that one possible mechanism of TFCC-induced cardio protection is mediated by blocking the oxidative stress. To clarify these mechanisms, we performed the in vitro study by A/R-induced cytotoxicity model in H9c2 cells. TFCC pretreatment prevented apoptosis, increased the expression of HO-1, and enhanced the nuclear translocation of Nrf2. TFCC also activated phosphorylation of AKT, whereas the addition of LY294002, which is the pharmacologic inhibitor of PI3K, blocked the TFCC-induced Nrf2/HO-1 activation and cytoprotective effect.
TFCC protects against myocardial injury and enhances cellular antioxidant defense capacity by inducing the phosphorylation of AKT, which subsequently activated the Nrf2/HO-1 signaling pathway.
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Objective
This study aimed to investigate the relationship between the duration of cardiopulmonary bypass (CPB) and stroke or early death in patients with acute type A aortic dissection (ATAAD) ...receiving total aortic arch replacement with the frozen elephant trunk procedure (TAR with FET).
Methods
A retrospective cohort study of 258 consecutive patients was conducted at Beijing Anzhen Hospital from December 2014 to June 2016. Patients who received TAR with FET for ATAAD were included. An adverse outcome (AO) was defined as 30-day mortality or stroke. Additionally, an AO was compared using propensity score matching.
Results
The incidence of AO was 13.6% (n = 35). The 30-day mortality rate was 10.8% and the stroke rate was 9.3%. Patients were aged 47.9 ± 10.6 years old. The duration of CPB was an independent predictor of occurrence of AO after adjusting for confounding factors by multivariable logistic regression analysis (odds ratio 1.101, 95% confidence interval 1.003–1.208). In matched analysis, CPB duration remained a risk factor of AO.
Conclusions
The duration of CPB is an independent predictor of AO in surgical repair for ATAAD. The underlying mechanisms of this association are important for developing improved prevention strategies.
Solid‐state Li secondary batteries may become high energy density storage devices for the next generation of electric vehicles, depending on the compatibility of electrode materials and suitable ...solid electrolytes. Specifically, it is a great challenge to obtain a stable interface between these solid electrolytes and cathodes. Herein, this issue can be effectively addressed by constructing a poly(acrylonitrile‐co‐butadiene) coated layer onto the surface of LiNi0.6Mn0.2Co0.2O2 cathode materials. The polymer layer plays a vital role in working as a protective shell to retard side reaction and ameliorate the contact of the solid–solid interface during the cycling process. In the resultant solid‐state batteries, both rate capacity (99 mA h g−1 at 3 C) and cycling stability (75% capacity retention after 400 cycles) are improved after coating. This impressive performance highlights the great importance of layer modification in the cathode and inspires the development of solid‐state batteries toward practical applications.
To mitigate the interfacial problems between cathode and solid electrolyte, a soft poly(acrylonitrile‐co‐butadiene) nanolayer is coated onto the cathode materials. The soft layer can not only sustain an admirable physical contact during cycling but also retard uncontrolled side reactions of the interface by shielding the particles from direct contact with the solid electrolyte.
In this paper, we propose a new unsupervised domain adaptation approach called Collaborative and Adversarial Network (CAN) through domain-collaborative and domain-adversarial training of neural ...networks. We add several domain classifiers on multiple CNN feature extraction blocks1, in which each domain classifier is connected to the hidden representations from one block and one loss function is defined based on the hidden presentation and the domain labels (e.g., source and target). We design a new loss function by integrating the losses from all blocks in order to learn domain informative representations from lower blocks through collaborative learning and learn domain uninformative representations from higher blocks through adversarial learning. We further extend our CAN method as Incremental CAN (iCAN), in which we iteratively select a set of pseudo-labelled target samples based on the image classifier and the last domain classifier from the previous training epoch and re-train our CAN model by using the enlarged training set. Comprehensive experiments on two benchmark datasets Office and ImageCLEF-DA clearly demonstrate the effectiveness of our newly proposed approaches CAN and iCAN for unsupervised domain adaptation.
Abstract
The explosion in demand for massive data processing and storage requires revolutionary memory technologies featuring ultrahigh speed, ultralong retention, ultrahigh capacity and ultralow ...energy consumption. Although a breakthrough in ultrafast floating-gate memory has been achieved very recently, it still suffers a high operation voltage (tens of volts) due to the Fowler–Nordheim tunnelling mechanism. It is still a great challenge to realize ultrafast nonvolatile storage with low operation voltage. Here we propose a floating-gate memory with a structure of MoS
2
/hBN/MoS
2
/graphdiyne oxide/WSe
2
, in which a threshold switching layer, graphdiyne oxide, instead of a dielectric blocking layer in conventional floating-gate memories, is used to connect the floating gate and control gate. The volatile threshold switching characteristic of graphdiyne oxide allows the direct charge injection from control gate to floating gate by applying a nanosecond voltage pulse (20 ns) with low magnitude (2 V), and restricts the injected charges in floating gate for a long-term retention (10 years) after the pulse. The high operation speed and low voltage endow the device with an ultralow energy consumption of 10 fJ. These results demonstrate a new strategy to develop next-generation high-speed low-energy nonvolatile memory.
The fact that the lifetime of photoluminescence is often difficult to access because of the weakness of the emission signals, seriously limits the possibility to gain local bioimaging information in ...time‐resolved luminescence probing. We aim to provide a solution to this problem by creating a general photophysical strategy based on the use of molecular probes designed for single‐luminophore dual thermally activated delayed fluorescence (TADF). The structural and conformational design makes the dual TADF strong in both diluted solution and in an aggregated state, thereby reducing sensitivity to oxygen quenching and enabling a unique dual‐channel time‐resolved imaging capability. As the two TADF signals show mutual complementarity during probing, a dual‐channel means that lifetime mapping is established to reduce the time‐resolved imaging distortion by 30–40 %. Consequently, the leading intracellular local imaging information is serialized and integrated, which allows comparison to any single time‐resolved signal, and leads to a significant improvement of the probing capacity.
Luminogens for a superior time‐resolved (TR) imaging effect with channel selectivity were achieved by engineering dual thermally activated delayed fluorescence (TADF) from anti‐Kasha/Kasha emission pathways. Intracellular local imaging information that is serialized and integrated was observed by calibrating the two TR signals. The technology is pertinent to precision medicine as TR signals are typically difficult to access in weak emission areas.
The built-in electric field generated by polar materials is one of the most effective strategies to promote the separation of photogenerated electron–hole pairs in the field of photocatalysis. ...However, because of the complexity and diversity of the built-in electric field in polar materials, it is not clear how to enhance the photocatalytic performance and how to control the polar electric field effectively. To this end, four-layered bismuth oxyhalides, BiOX, and BiOXO3 (X = Br, I) were synthesized by a simple hydrothermal method. X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy analysis confirmed that they all have the structure characteristics of a sillenite phase. Scanning electron microscopy images show that they all have the morphology of nanosheets. Among them, BiOBrO3 was successfully synthesized and characterized for the first time in the present work. The order of photocatalytic performance (including carrier’s lifetime, photocurrent density, and H2 evolution rate) of the four compounds is listed as follows: BiOBrO3 > BiOI > BiOIO3 > BiOBr. In the bulk of the BiOXO3 photocatalyst, the spontaneous polar built-in electric field along the 001 direction is the crucial factor to inhibit the recombination of photogenerated electron–hole pairs, while the surface polar electric field in BiOI can outstandingly inhibit the recombination of photogenerated electron–hole pairs due to the breaking of the mirror symmetry. Therefore, regulating the microstructure and composition of the structure unit, which generates the built-in electric field, can indeed control the magnitude, direction, and effects of built-in electric fields. In practice, we should carefully adjust the strategy according to the actual situation so as to reasonably design and use the polar electric field, giving full play to its role and enhancing the photocatalytic performance.
Layered Ni‐rich lithium transition metal oxides are promising battery cathodes due to their high specific capacity, but their poor cycling stability due to intergranular cracks in secondary particles ...restricts their practical applications. Surface engineering is an effective strategy for improving a cathode's cycling stability, but most reported surface coatings cannot adapt to the dynamic volume changes of cathodes. Herein, a self‐adaptive polymer (polyrotaxane‐co‐poly(acrylic acid)) interfacial layer is built on LiNi0.6Co0.2Mn0.2O2. The polymer layer with a slide‐ring structure exhibits high toughness and can withstand the stress caused by particle volume changes, which can prevent the cracking of particles. In addition, the slide‐ring polymer acts as a physicochemical barrier that suppresses surface side reactions and alleviates the dissolution of transition metallic ions, which ensures stable cycling performance. Thus, the as‐prepared cathode shows significantly improved long‐term cycling stability in situations in which cracks may easily occur, especially under high‐rate, high‐voltage, and high‐temperature conditions.
A slide‐ring polymer featuring high elasticity and self‐adaptive ability is designed to improve the performance of lithium‐ion batteries via relieving the cracks of cathode particles and retarding parasitic interfacial side reactions during cycling.
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